Sand blasting machine



Feb. 24,1942. M. T. swlsHER 2,274,172-

SAND BLASTING MACHINE Filed April 6, 1940 4 Sheets-Sheet l ffm@- W INVENTOR.

A T TORNEY Feb. 24, 1942. M- T. svyl'sHEl-e-` 2,274,172

SAND BLASTING MACHINE F'led April 6, 1940 4 Sheets-Sheet 2 l INVENTOR.

ATTORNEY Feb. 24, 194147..n M T, swlsHER 2,274,172

SAND BLASTINGMACHINE Filed April 6, 1940 INVENTOR.

ATTORNEY 4 Sheets-Sheet 3 l Feb. 24, 1942.

M. T. SWISHER SAND BLASTING MACHINE Filed April e; 1940 I 4 Sheets-Sheet 4 IN VEN TOR.

ATTORNEY on cylindrical articles.

Patented Feb. 24, 194.9.

nturist)N STATES PATENT @Price l A2,274,172 SAND BLA'sTINGMAoHmE Mur-ray lSwisher, fClar-'tom-Pa. .appncationnprn c, 1940', seria; No. 328,301 aclaims'. d (orsi-49) This .invention vrelates to sand blasting ymachines and is directed 4lto -more particularly an apparatus wherein the abrasive materialismojected and directed against the Work by means .of `an impeller Wheel.

One of the objects of the present invention is to .provide a centrifugal abrading apparatus in which the impeller wheel, when .rotated at .high speed,` produces a :strong current of air, thereby greatly increasing theforce at which vthe `abrasive material deposited on said impeller wheel is prodented against lthe work. v y

Anotherfobjeot -of the invention -,is to provide a centrifugal abrading .machine `with animpeller wheelassembly in which the location of the feeding spout through which the abrasive material is fed to the impeller wheel-may be varied.

Still another'object ,of the invention is to provide an -abrading apparatus in whichfthe amount of abrading material fed to the `impeller wheel maybe controlled Without changing any parts. Yet `another objectof the invention is to provide a centrifugal abrading machine which is yadapted to be used for `producing decorative designs, printing, etc. .on glass `or metal by .removing `the .luster or .smooth surfaces therefrom.

Another objectoi the invention .is to .provide a .centrifugalvabrading machine in which articles 4with large .surfaces maybe evenly .sand blasted, yet the stream rof abrading material projected .and directed against the articles does Vnot necessarily strike lthe whole surface which is to be sand blasted at one time. t y y vA still `further object 'of the invention tisto provide a centrifugal abrading apparatus `in which the Work support may, be raised or lowered and turned fory a` predetermined Aportion of a circle :at every upv movement of the work support. v

- lAnother object of the invention is -to ,provide a centrifugal abradng l-machine in which `the `work ksupport may be continuously rotated for producing sand blasteddesigns, lettering, etc.

Further objects lof the invention are 4to provide an apparatus of the classset forth. which is `simple in its construction and arrangements, ef- .ficientin its use, operable by inexperienced persons and inexpensive to manufacture, i g

To the accomplishment of these and such other objects as may hereafter appear the invention consists of the novel construction, .combination `.and Aarrangement of y parts `herein specifically described vand ,illustratedy in the accompanying vdrawings wherein `is shown lan .embodiment of the `invention, `but it .is `to `be understood that changes,varations Aand modifications Vmay be resorted to which-come ,within the scope 4of .the claims -hereunto appended.l

In the .drawings whereinlike `numerals, .of .referencedesignate .corresponding parts throughout the several views, l l

Figure 1 4is a side elevation of Athe .device einbodyingtthe invention, partly incross sectionand the `sidewalls (eliminated. 1

Figure .2 is a front elevation of Figure l taken substantially `on line 2-2 of lFigure 1.

Figure 3is'atop viewof Figures Land 2.

Figure 4 is asectional View takenon line ll-ll of Figure 1. l

Figure `5 is a fragmentary view oi the cooperating parts by vmeans of which the work board upon which the articles to A be `sand `blasted are Y mounted 1s intermittently rotated, in this case for a one quarter turn.

:Figurei isa `view similar 'to Figure!) showing the pawl 'in contact withvone of the studs of the rotatable stud wheel secured to the `Work board.

lFigure 7 .is yanenlarged top `view of the hollow disc fwhich is tmovably mounted l,on the upper wall of the impeller wheel housing serving to-supplyair to the impeller wheelandalso serving to deposit abrading :material on vthe impeller wheel in vari- .ous radial vpositions thereby varying Ithe angular spray force .of the abradingmaterial. e Figure .is a sectional detail -side view online 8--8 :of Figure 7 showing ;thefeature`s outlined above and, -in-addition, indicating by arrows, the travel of the air stream `created by the impeller Wheel. Figure 9 isa -fragmentaryvoutline side viewof Figure B.

yFigure V10 =is a fragmentary ytop view of the impeller wheel. Y i

Figure 11 is airagmentary,perspective view of the impeller wheel including one ofthe blades therefor.

,v-Figure 12 is across sectional side view of a modied form of impeller wheel assembly .showing Aa solid 4disc or block provided with a large central air intake opening. Y

yFigure 13 is an enlarged cross section of one ,of vthe suction cups ,as used yon the work board for` holding ilat articles while sand blasting.

Figure 14 is a `perspective view `of the sand ybin as used in the invention having part of the Yside Wallsbrokenawayto showthe interior thereof.

yFigurelfis. a top view of Figure 14. .Figure 16 v represents a fragmentary sectionalI View on the line |6|6 of Figure 15, the upper portion of the sand bin being shown broken away.

Figure 17 is an enlarged perspective View of the handle bar of the selector disc including the locking mechanism for the latter.

Figure 18 illustrates a side view of the complete apparatus as shown in Figure 1 with parts of the walls broken away and as used to sand blast round articles, such as glasses, etc.

Figure 19 is a top View of Figure 18, the impeller wheel cabinet being broken away.

Figure 20 is a fragmentary front elevation sectioned on line Z6-26 of Figure 19.

Referring now to Figures l 2 and 3 inclusive, the apparatus shown consists in general of two distinctive cabinets, the impeller wheel cabinet and the work cabinet 26.

Cabinet 25 contains an impeller wheel 21 mounted for rotation on a Vertical shaft 28 which is rotatably mounted in ball bearings 29 and 36 supported on horizontally disposed cross strips 3| and 32 respectively, as shown.

Said vertical shaft 28 is shown driven by means of an endless belt 33 trained over a set of pulleys 34 and the power being supplied by an electric motor 35.

The lower portion of said cabinet 25 is provided with an impeller housing 36, preferably of rectangular contour, having side walls 31 and 38, a rear wall 36, an inclined bottom 48 and a horizontal top wall 4|. The front portion 42'of said housing 36 extends slightly beyond the cabinet 25 and terminates into a rectangular flanged end 43.

Said top wall 4| is provided with a bore 44 and a counterbore adapted to receive an annular block 46 which is shown on an enlarged scale in Figure 12 of the drawings. f

The block 46 has an annular flanged extension 41 which rests in said counterbore 45 of top wall 4| and is held in sliding contact by flat springs 48 in a manner as shown in Figure 7. The large central aperture 49 in block 46 serves to accommodate the impeller shaft 28 and to permit air to enter the impeller wheel 21.

Block 46 is also provided with an outwardly extending operating handle 56 secured to the top face 5| thereof by which the block 46 may be horizontally and circumferentially shifted when it is desired to change the circumferential location of the sand feedingaperture'52 in which is inserted the free end of a exible tube 53 leading from the bottom of the sand box 54 (Figures 1 and 16). By shifting said block 46 as above described the location of the sand feeding outlet 52 Athrough which the abrading material is discharged by gravity to the impeller Wheel 21 may be readily changed, thereby causing an increase or decrease of the angular spray of the abrasive against 'the work to be sand blasted.

The circumferential movement of said block 46 may be checked by stop pins 55 or 56 as shown, or otherwise. A

In order to obtain the proper suction effect of the impeller wheel 21 the top portion of the latter should be, when assembled, in close parallel alignment with the lower face 51 of block 46 as shown in Figure 12. y

Block 58 (Figures 7 and 8) `shows a modified construction of the block 46 heretofore mentioned and the former comprises a top discl 58 provided with an annular flange 66, and a bot- .tom disc 6|, both of which are securely held apart by spacers 62 so as to form a hollow structure.

The outer peripheries of said discs 58 and 6| are in alignment and are covered with a screen 63.

Top disc 59 is provided with a central bore 64 of sufficient size to clear the impeller shaft 28 while the bottom disc 6| has a central bore 64a of larger dimension. In this construction, the block 58 serves as an air intake means which supplies the impeller wheel 21. The air for the impeller wheel 21 enters through the screen 63 secured around the periphery of the hollow block 58 and leaves through bore 64a of the bottom disc 6|.

The flexible tube 53 from sand bo-X 54 is inserted in coincident openings 65 and 66 having a sleeve 61 secured therebetween. Otherwise the construction and operation of block 58 is same as for block 46 previously described.

'Ihe impeller wheel 21 consists of an annular base-plate 68 having a plurality of blades 69 (Figure 11) secured thereon and spaced and placed as shown in Figure l0 of the drawings. Said blades 69 are preferably formed of sheet material of substantially triangular outline having the edge 18 bent upwardly and inwardly as shown and indicated by the numeral 1| in Figure 11.

Abrasive material is supplied to the impeller wheel 21 from a sand box 54 which is provided with anfinclined bottom wall 12 which merges into the horizontal bottom 13 as best shown in Figures lel to 16 inclusive. This horizontal bottom 13 is provided with an out-passage 14 for the sand having a flexible tube 53 inserted and secured therein, the free end of which terminates in the feeding aperture 52 of block 46, as heretofore described.

The abrasive material as herein used includes such as finely divided dry sand or artificial abrasiVes such as metallic grit or other artificial cutting material and is adapted to gravitate from the sand-box 54 to block 46 and then be deposited, also by gravity upon the impeller wheel 21.

It is often required to project a small or a large quantity of abrasive without changing the speed of the impeller wheel 21, this is accomplished by providing the out-passage 14 of sand box bottom 13 with a manually operated selecting disc element 15 which consists of a circular, substantially flat disc 16 provided, in this case with four differently sized openings 11 on a common radius and equally spaced. When assembled, this disc 16 is so arranged that by turning the rod 18 one of the openings 11 of disc 16 will register with the -out-passage 14 which, of course, must be larger than any of the openings 11 of disc 16. Rod 18 is centrally secured to the latter and the stub end 19 is rotatably'inserted in aperture 88 of sand box bottom 13 and held in position by a nut 8| or otherwise.

The upper end 82 of said'rod 18 extends upwardly to a point near the upper edge 83 of sand box 54 and is rotatably retained in a star-like element 84 which is fastened to the sand box wall by means of an angle piece 85. A

g Referring now to Figure 17 there is shown a perspective View of the selecting device by means of which the desired size of opening 11 of disc 16 will register with the out-passage 14 of sand box bottom 13 without requiring the sand box to be emptied. The upper end 86 of rod 18 is preferably flattened and bent over to form a handle 81 by means of which the selectorv disc 16 may be turned. Slightly below said handle 81 is pivotally mountedV the locking pawl 88, the lower-end of which terminates into a strip extension 89 which `observe the progress of the work is adapted to engage oneof the -fourf'slots l@900i star-like yelement 584. Each of said slots 90 correspond with one ci the openings 11 of disc '16 and the star element 84 may Abe marked, as shown, `to identify the'size of opening 11 registering with out-passage 14.

The upper portion of said locking pawl `80 is bent over vas shown, to form ahandle 9| so 'as to enable the operator to grip the rod handle -8-1 Land the pawl handle 9| at the same time. A lea-f spring 92 is secured to the underside of said -pawl handle A9| and the free end of the spring rest on the rod handle 81.

In operating the selecting disc element the Workman grips with one hand both handles 01 and 9| thereby removing the extension 89 (see dot and dash lines in Figure 17) out of engagement of one of the slots 90 of the star yelement 84. By turning handles 81 and 0| tothe desired slot 90 and releasing the spring tensioned handle 9| the extensions!! will enter the slot and thereby prevent rotation of the disc element 15. Y

The work cabinet 26 as shown in Figures 1, 3 and 4 serves as a work chamber in which the articles to be vdecorated are subjected to the sand blast.

The 'same 4comprises `a rectangular box having sidewalls Atill and A95, a rear wall v9B, a front wall 91 and an inclined bottom 9S. The spent sand may be removed through the opening 09 located in the `lowerrnost end of front wall "81 `by idrop-- ping the hinged door |00. riihe open upper end of cabinet 26 through which the workman may or insert the work is provided with a hinged Acover 10|.

The rear wall 90 of cabinet 20 is provided with `a rectangular opening 4|`|l2 which substantially corresponds to the rectangular flanged end 43 of the impeller wheel cabinet 25. Aigasket |03 may be inserted between said rear ywall 06 and said yflanged end 43 before joining them together to prevent dust to escape around the seam.

Said cabinet 26 is provided in each corner, facing the front, with a pair of spaced apart upright rails support |96 is slidingly inserted. Said support |06 may be raised or lowered .by means of a crank handle |01 directly attached to one end of a stub shaft |08 which is rotatably supported in the upper iront wall 01, said stub shaft |08 is secured to a grooved pulley |09 to which one end of a cable or :rope `lli) is secured while the other end of said rope is fastened to the work board `support |f06 in arman- `ner as shown in Figures 1, 3 and 4, or otherwise.

As previously mentioned, the herewith described apparatus is especially adapted to sand blast flat articles of glass, metal or other suitable materials of a size equalling the area of the `work board or if desired several smaller flat objects of a total area of the work board may be sand blasted at one time, but it should be noted that only a substantially narrow vband of abrasive is expelled by centrifugal force from the impeller-.wheel 21 and strikes the articles to be sand blasted. It features of the present invention to, not only move the work board A`I on which `the articles to be sand blasted are secured in a vertical direction but also impart an intermittent circular motion to the same.

It is for that reason that said work board is mounted for intermittent circular motion upon the work board support |08 and this is accom@ |04 and |05 in which a work-board while the other end of I is therefore one of .the main` plished by providing fa pin connection i2 :which is rotatably Isupported `in the 'work board support |06.

This pin connection ||2 has securely 'mounted on the end H3 facing the impeller wheel v21 the work board and on the opposite end I4 a pin wheel H5, in other words, the workboard is mounted on `one side of the Work board support .|06 and the pin wheel H5 on vthe other side of the same.

vA pin wheel pawl |`|6 which cooperates with pin wheel -l||5 -is mounted on the inner Vface of front wall91'in close proximity of the .pulleyf.v|09.

'In operation, the workman :slowly turns the crank-"handle |01, thereby raising the workboard support |05 including 'of course `the workboard H-'I and the pin wheel H5 until the lowermost edge l||1 of said pawl H6 strikes one of therpin wheel pins Hi8 (Figure 6) thereby causing the pinwheel ||5 and the work board toi-rotate', in this case, since there are four pins limon the pin wheel, for a quarter turn, afterwhich the springV tensioned cam lever |19 `retains the `rwork board and pin wheel lili-5 in a positionwa's shown in Figure 5.

It should be observed, thatthe work lboard sup port |06 including the work board when in up position will extend outwardly kof the work kcabinet 26 and in that position flat articles .|20 to 'be sand blasted Imay be applied and retained in position lby suitable rubber suction cups 1|2l, mounted on `the work Aboard I in Aa well .known manner (Figures l, 3, 4 and 13). i

In order to keep the work board HAI `and vits support |06 in up position, while placing or removing work, the peripheral edge 1220i pulley |09 Ifacing' the inner side of front wall '91 is provided with ratchet teeth |23 ycooperating with a ratchet pawl |24. VThe latter may be brought out of lengagement ofy the ratchet teeth from the exterior of the work cabinet 2t by .a knob .125, or otherwise (Figures 1 and 4). i

The operation of the work vboard mechanism has been illustrated as manually operated but'it is clear that it may be operated from the saine motor which spins the impeller wheel.

In general, the 'operation of the device `is .as follows: Y il Assuming that the sand box -54 is filled with abrasive, the electric motor is connected to alsup ply line and flat articles are'hcld by suction cups 12| on the'work board 1H; ready to be decorated by sand blasting.

As the electric current is turned on 'the motor spins the impeller wheel 21 which receives abrasive material from the sand box 5t 'by gravity through block Mi. The abr-asive is thrown horizontally and outwardly and against `the work to be sand blasted by centrifugal force aided by the airstream and vacuum developed by :the blades of the impeller wheel y21. At that stage,'the abra Asive so discharged against vthe work w'ouldsand Ablast a narrow strip of the work only and it is for that reason that it is necessary to move the work board up and downwardly and in addition to turn it at every up movement for a quarter of a turn.

As the operator slowly turns the crank handle |01 in clockwise direction the work board HI is raised until one of the yfour pins I8 of pin wheel "l I5 strikes the pin wheel pawl H6 thereby imparting a quarter'turn to the work board as previously explained.

The operator now slowly turns the crank handle |01 in a counter clockwise direction thereby lowering the work board until it strikes the bottom, and againthe operator raises the Work board in a manner as heretofore described. These operations are repeated until the work is completed.

In this manner the articles will be sand blasted in compounded directions which in turn will produce .an even and smooth sand blasted nish.

Referring now more particularly to Figures 18, 19 and 20 there is shown an attachment to the above described construction by means of which cylindrical articles may be sand blasted.

In this attachment three pedestals |26, |21 and |28 are mounted in axial alignment on a supporting strap |29, as shown, Pedestal |21 is rigidly mounted on said strap |29 and this pedestal rotatably supports a short shaft |30. The latter extends at both ends of bearing |3| and has annular discs |32 provided with hubs |33 mounted thereon. A rounded soft rubber pad |34 is cemented or otherwise secured to the outer face of disc |32. n

' Pedestal |26 is slidably mounted on supporting strap |29 having a disc |32 and rubber pad |34 mounted on the inner end of shaft |35, while the opposite end of the latter is provided with a collar |36 which prevents the shaft from sliding out of the bearing |31.

Pedestal |28 is of similar construction as pedestal |26 with the exception that the shaft |38 extends outwardly of the work cabinet 26 and carries a pulley |39 which may be connected by a belt |40 to an electric motor (not shown) or otherwise.

Pedestal |26 and |28 are slidably supported on said strap |29 and may be moved axially by means of a screw connection |4|, one end of which extends outwardly of cabinet 26, as shown. Of course, all of said shafts |30, |35 and |38 are in horizontal alignment with the impeller wheel 21 as best shown in Figure 18.

In operation, glasses or other cylindrical objects may be clamped between the soft rubber pads |34 or freed from the same by turning the knob |42 of screw connection |4I, but otherwise the operation is identical with the apparatus adapted especially for sand blasting flat articles such as previously described.

In View of the above, it is believed that the various features of the present invention will be clear Without further elaboration, and it will be seen that with the apparatus herein described, the several objects of the invention are achieved and other advantageous results are attained.

The invention may be embodied in other specific forms without departing from the spirit l or essential characteristics thereof and the present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being expressed by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

I claim:

1. In an abrading machine, a frame, a housing mounted horizontally in said frame and open at its front end, a shaft rotatably mounted vertically in the frame over said housing with its `f lower portion entering the housing, an impeller wheel fixed upon the shaft within the housing; a hollow block surrounding, the shaft over said Wheel and having spaced upper and lower walls and a peripheral Wall of forarninous material for admitting air into the block, the lower Wall of the block being formed with an opening about the shaft for delivering air to the center of the impeller wheel, upstanding blades extending substantially radially of the impeller wheel and having sideanges along their upper edges, said blades having their inner ends spaced from each other and spaced from the shaft, a sand box in said frame over said housing having a tube leading from the sand box for delivering sand through the block and onto the impeller wheel, means for rotating said shaft to spin the wheel and discharge sand therefrom through the open end of thehousing, a work chamber having an inlet registering with the open end of the housing, and means in the work chamber for supporting an article in position to be acted upon by a sand blast entering the work chamber from said housing.

2. In an abrading machine, a frame, a housing in said frame open at its front end, a shaft rotatably mounted in said frame and entering the housing, an impeller in said housing actuated by said shaft, a sand box mounted in said frame and having an outlet tube for delivering sand to the impeller wheel, a work chamber disposed verv tically in front of said frame and having its rear wall secured to the front end of said housing and formed with an inlet registering with the open end of the housing for discharge of a sand blast from the housing into the work chamber, a support shiftable vertically in the work chamber, a Work holder carried by the support and rotatable about a horizontal axis, means for shifting the support vertically, and means for imparting partial turns to the work holder in step-by-step movements during vertical movement of the support.

3. In an abrading machine, a frame, a housing mounted horizontally in said frame and open at its front end, an impeller operating in the housing for discharging a sand blast through the open end thereof, a sand box mounted in said frame and having an outlet tube for delivering sand to the impeller, a vertical work chamber having a rear wall secured to the front end of said housing and formed with an inlet opening registering With the open end of the housing, vertical tracks in the work chamber, a support slidable vertically along the tracks, a shaft journaled horizontally through said support, a work holder xed to the rear end of the shaft, means for securing work to be sand blasted against the rear face of the work holder, a disc fixed to the front end of the shaft, pins extending from said disc in spaced relation to each other circumferentially thereof, a pawl yieldably held in position to engage said pins and hold the shaft and the work holder against turning, means for shifting the support upwardly and then downwardly along the tracks for reciprocating movement across a sand blast, and an abutment for engaging a pin as the support approaches one end of its reciprocating movement and imparting turning adjustment to the shaft and the work holder.

MURRAY T. SWSHER. 

